Cell membranes and cell-surfaces contain phospholipids, glycolipids, and glycoproteins which are believed to be involved in such phenomena as contact inhibition, in which interactions between glycolipid or glycoprotein components of the cell surface are thought to play a role. We propose to study the biosynthesis and assembly of these components into bacterial membranes, with emphasis upon the glycosyl transferases involved in biosynthesis of bacterial lipopolysaccharides. The role of protein-lipid interactions on synthesis of the polysaccharide portion of the molecule and on assembly of the membrane-bound system will be studied by biochemical methods, monolayer techniques and physical methods.